Tool for connecting insulated wires with attachment plug blades



Nov. 30, 1943.

N. CHIRE LSTEIN TOOL FOR CONNECTING INSULATED WIRE WITH ATTACHMENT PLUG BLADES Filed'March 26 1942 INVENTOR NATHAN CHIRELSTEIN BY ,ATTRW Patented Nov. 30, 1943 TOOL FOR CONNECTING INSULATED WIRES WITH ATTACHMENT PLUG BLADES Nathan ,Chirelstein, Maplewood, N. J.

Application-March 26, 1942, Serial No. 436,301

1 Claim.

The invention here disclosed relates to the connection of wires with the contact blades of attachment plugs or other electrical devices and is a continuation-in-part of co-pending application for Patent Ser. No. 394,069 filed May 19. 1941 and issued Aug. 4, 1942, as Patent 2,292,049.

Objects of the invention are to provide simple and. practical mechanism for connecting insulated wires in interlocked strain relief engagement with contact blades or the like, and to accomplish such connection without injuring the insulation of the wires, or harming the wires or contacts.

Further, it is a purpose of the invention, to provide simple means which will position and locate the wires and contacts in the relation in which they are to be associated and which can be operated to quickly and easily assemble such parts.

Other desirable objects and the novel features of the invention by which the purposes of the invention are attained are hereinafter set forth, illustrated in the accompanying drawing and broadly covered in the claim.

In the drawing, there is shown a practical commercial embodiment of the invention, but it is realized that the same may be modified in various ways, all within the true intent and broad scope of the invention as hereinafter defined and claimed.

Fig. 1 is a side elevation of a hand tool embodying features of the invention and shown with the jaws open and an insulated wire and contact blade positioned therebetween.

Fig. 2 is an enlarged cross-sectional view as on the line 22 of Fig. 1.

Fig. 3 is a view similar to Fig. 1, showing the jaws closed and the insulated wire fully engaged in the holding slot in the blade.

Fig. 4 is an enlarged cross-sectional View as on line 44 of Fig. 3.

The tool shown is of the pliers type, comprising pivoted handles 5, B, carrying opposed jaws I, 8.

These jaws are longitudinally grooved in their opposing faces to receive, hold and position the end portion of a contact blade 9.

Thus the lower jaw I, has a narrow contact blade receiving groove l0, extending a short distance inwardly from the end thereof.

Similarly, the upper jaw 8, has a corresponding contact blade receiving groove or seat II.

The upper jaw has a shallow rounded groove I2, extending transversely across the face of the same, intercepting the deeper longitudinally extending groove H.

The contact blades, as'most clearly shown-in Fig. 1, have keyhole type notches in the'edge s of the same, consisting of narrow entranceslots I3, opening into rounded enlargements [4.

The wires I5, which are to be assembled with the blades have rubber or other resilientinsulation l6. There is a special relation between such wire and the notch in the blade, in that the enlargement at the inner end of the notch is enough smaller than the insulating covering of the wire to compressibly grip and hold the latter and the entrance portion I3, is narrow enough to reduce the insulation, in passage to the holding opening without injury and to reliably retain the wire in the latter position.

Operation In use, the end of the blade is inserted in the lower jaw with the notch uppermost and the wire located transversely across the entrance to the notch, substantially as shown in Figs. 1 and 2. With the parts so positioned, the jaws are closed and in this closing movement, the rounded shallow transverse groove l2, in the upper jaw engages over the upper side of the insulation, at opposite sides of the blade and forces the wire downward in the notch to the final seated position indicated in Figs. 3 and 4. In the movement down through the narrow entrance portion 13, the insulation is squeezed to a considerable extent, but has space to fiow during such compression, in the upper portion of the longitudinal groove II, in the upper jaw. In the fully seated relation, the insulation expands slightly in the enlarged portion I4, of the notch, but as the diameter of this portion is appreciably smaller than the normal diameter of the insulating cover, the insulation and hence the wire within it will be firmly gripped and held in the notch.

In the final, fully seated position, Figs. 3 and 4, the wire is firmly and positively held by its insulating coating, in the notch in the blade and hence a good firm strain relief connection is provided between the wire and blade. The electrical connection between the wire and blade can be made by removing part of the insulation from the wire, to enable the bare wire to contact the blade at one or more points.

The shallow cross groove or grooves I2, in the upper jaw at opposite sides of the blade receiving seat ll, provide ample bearing surface engaging the insulation of the wire to avoid any injury to such insulation, during the period of compressing and forcing the insulated wire down into the holding notch.

A fairly deep groove I 0, is desirable, to hold the blade upright in the lower jaw and if with such a deep groove there is a tendency of the insulation to objectionably engage the face of the lower jaw at opposite sides of the blade, said lower jaw may be slightly relieved by shallow rounded cross grooves, such as indicated at H.

The companion longitudinal grooves or seats II], I I, in the ends of the jaws are preferably of a length and depth to fully position the blade both to locate the wire receiving notch in line with the wire engaging cross groove in the upper jaw and to operate as stops, Fig. 3, engaging opposite edges of the blade to limit the wire seating movement of the blades, so they can not possibly injure the insulation of the Wire. 7

While shown as a hand tool, it'will be evident that the novel features of the invention may be incorporated in a press or other form of machine tool.

In lieu of, or in addition to utilizing the inserted blade as a stop to limit the closing movement of the jaws, there may be provided an adjustable stop, such as indicated at l8, threaded on a screw stud 19, in position to limit the closing movement of the handles and hence the closing action of the jaws.

What is claimed is:

A tool for forcing an insulated wire transverseattachment plug contact blade and comprising companion jaws having narrow, deep, substantially parallel-sided longitudinal registering grooves in the opposed faces of the same, opening outward through the ends of the jaws and extending inward a distance sufiicient to locate a contact blade seated therein with the keyhole notch in said blade disposed a predetermined distance inward from the ends of said jaws and one of said jaws having a shallow rounded groove extending transversely entirely across that face of the same which is opposed to the other jaw, at that predetermined distance inward where the keyhole notch in the blade will be so located and said shallow transverse groove crossing the narrow longitudinal notch in said jaw, open at both ends to receive an insulated wire which has been located over the entrance to said transverse notch in the blade and thereby arranged to press on the insulated wire at opposite sides of a blade located and supported on edge in the narrow longitudinal groove in the other jaw and to force said insulated wire down into seated position in said keyhole notch as said jaws come together over said inserted blade and said thus located wire.

NATHAN CHIRELSTEIN.

ly in through a keyhole notch in the edge of an 

